Method and apparatus for dispensing liquefied gases



Jan. 30, i945. o. A. HANSEN METHOD AND APPARATUS FOR DISPENSING LIQUEFIED`GASES Filed May 20, 1943 Patented Jan'. 30, 1945 UNITED STATES PATENT GFF ICE METHOD AND APPARATUS FOR DISPENS- ING LIQUEFIED GASES a corporation of Ohio Application May 20, 1943, Serial No. 487,793

9Claims.

The invention is concerned with the storage and dispensation of liqueiied gases, and is particularly directed to the transfer of charges of the material from a transport or main storage container to a. second container which serves as the immediate source of supply of the material for industrial uses and which accordingly has associated therewith means for withdrawing the material as required and vaporizing it andheating the gases to a condition suitable `for such use. Liquids of the character to which the invention is applicable are highly volatile, having a boiling point at atmospheric pressure below 273 K. The invention is particularly useful in the handling and dispensing of liquid oxygen, the boiling point of which at atmospheric pressure is in the range below 233 K.

An economical means of rendering the material avilable as required for use is toprovide a moderate size container. commonly referred to as a "converter, in which a supply of the material is maintained under a pressure equal at least to the service pressure required, the material being primarily in the liquid phase but being present also in the gas phase in the container space immediately over the liquid contents. Such an arrangement requires, of course, intermittent recharging of the converter, and the present invention is concerned with the recharging methods.

The highly volatile character of the liquid handled and the extremely low temperature thereof, together with the desirability of'avoiding losses of the material and avoiding also any substantial interruption in the service to the consuming apparatus introduces diilicuities and problems not exhibited in the handling of ordinary liquids. If upon a recharging operation the container is q maintained otherwise completely closed the gas space is progressively reduced in volume, with corresponding compression of the gas present. This usually would result in an excessive pressure, although not necessarily so since the condition is affected by the refrigerating characteristics of the liquid, and also the raising oi the boiling point under increased pressure may in itself result in some liquefaction of the 'compressed gases. Heat leakage into the container adds another uncertain and variable factor.

The present invention is adapted to meet these conditions and to take advantage in fact of the refrigeration capacity of the added liquid. In accordance with the method thereof the recharging is accomplished in a manner to control the pressure in the container by the effect of the added liquid, and the pressure may be maintained substantially constant at any selected value, such as that desired for supplying the material for its customary industrial uses. A particular feature is an arrangement and method of operation whereby the recharging liquid is 10 tively little change in heat content of the gas in the space over the liquid occurs during the recharging operation and, accordingly, the reduction in the gas volume results in progressively increased pressure which may rise to undesirable and dangerous values; but if the liquidis delivered to and through the gas space the added liquid, because of the pressure exerted thereon in forcing it into the receiver, will be subcooled and the refrigeration contained therein will serve to condense part of the gas in the container, correspondingly reducing the pressure thereof. By selective delivery to the gas and liquid phase the pressure in the receiving container may be maintained substantially constant at a predetermined value.

Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and

the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to eiiect such steps, all as exemplified in the following detailed disclosure, and the scope of which invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the inventionreference should be had to the following detailed description taken in 4o connection with the accompanying drawing, in

which:

Fig. 1 is a view partly in section and partly in elevation showing a. system for transferring liquid oxygen from a portable container to a receiving container in accordance with the invention; and

Fig. 2 is a view partly in elevation and partly y in section taken on the line 2-2 of Fig. 1 showing in general an arrangement of a rotary pump with driving means therefor which may be used in the combination of Fig. 1.

in part. The main supply source may be either a large stationary storage container, or, as particularly shown` a transport container.

Referring now to the drawing and particularly to Fig. 1, I denotes a. wheeled chassis of a motor vehicle powered by suitable means, such as an internal combustion motor. Such chassis here supports a transport container, shown as comprising a casing I I and a liquid holding vessel I2, the casing being spaced from the vessel I2, in order to provide a suitable space I3 for insulating purposes, for example, one which may be filled with powdered insulating material, such as magnesium carbonate. The container I2 may, if desired, be thick-walled sowas to withstand high pressures. The container I2 is also shown provided with a clo'sable vent Il.

Associated with the transport container is a suitable liquid transferring means which may comprise a mechanical pumping device, such as a. turbine pump I5, having one or more stages, depending on the kind of service it is required to give. The pump is provided with suitable driving means, for example, an electric motor, shown at M in Fig. 2. The power for such motor is had from any convenient source. as from a power line run from an outlet or plug-in receptacle at the consuming installation. It is also contemplated using a power take-oil' on the torque shaft of the motor vehicle as the source of driving power, as set forth in my copending application, Serial No. 369,023, led December 7, 1940.

The pump I5 has a liquid supply connection I6 connected to withdraw liquid from a point substantially at the bottom of the vessel I2 and convey it to the inlet of pump I5. A connection Il is also provided and arranged to convey away the discharge from the outlet of the pump; a flexible portion I8 being attached by means of a suitable coupling. Suitable conduits and controls are provided to enable the liquid to be delivered selectively either to the liquid or gas phase of ythe receiver container. To this end the delivery line Il divides into two branches I9 and I 9' respectively. The branch I9' also has in shunt therewith a conduit I9". The control and operation of these lines will be described later.

The liquid receiving or storage container is designated and comprises part of a system arranged to supply the consuming apparatus with gaseous or vaporized liquid oxygen under a desired pressure. The pressure vessel 20 here employed preferably has a spaced inner basket 2| for holding the liquid, and reducing the amount of heat otherwise transferred thereto by conduction. 'I'he wall of vessel 20 is made sufiiciently thick to withstand the operating pressure, for example, a pressure of 150 lbs. per square inch gauge. The vessel 20 is connected to discharge into suitable heating and liquid vaporizing devices which are operatively associated therewith, the arrangement comprising a socalled cold converter system. Such connections are shown as comprising a gas phase withdrawal connection 24 leading from the gas space of the vessel 20 and discharging into a heating coil 25 from which the heated gas passes to a consuming device. Connection 24 is provided with a shut-off valve such as shown at 24'.

A liquid phase Withdrawal connection 28 is also provided, which leads from a point relatively close to the bottom of the liquid holding vessel and discharges into a heating coil 21. 'I'his line also has a shut-oil' valve as shown at 26'. The discharge from the coil 21 is led through a. reentrant connection 2B which traverses a liquid column or side conduit 23 that is adjacent vessel 20; an automatic :dow controller. such as the regulator shown at 23, being preferably introduced in connection 28 at a suitable point. 'I'he conduit 29 is connected to the interior of vessel 20, or more exactly to that of the basket 2|, at its ends at points both above and below the normal liquid level in the manner taught in United States Letters Patent No. 1,950,353, issued in the name of L. I. Dana on March 6, 1934. The liquid in the column becomes heated and serves to accelerate the withdrawal of liquid from the container and to hasten the vaporization of oxygen in the cold converter system. 'I'he connection 28 leads out again to the exterior of the container to a place of use and preferably includes another heating coil 30.

Suitable heating media are supplied for heating the coils 25, 21, and 30, comprising the three heating means here associated with the receiving container and denoted generally at H.

To achieve priming of the pump I5, a connection 3| having a. valve 32 is provided and arranged to lead from the outlet of the pump to the gas space of the vessel I2.

The branch I9 of the discharge connection from pump I5 leads to the bottom of container 20 for delivery of liquid directly to the liquid phase of the container, and branch I9 leads to the upper part of container 25 for delivery to and through the gas phase. Suitable valve control means are provided for selectively apportioning the delivery through these lines as desired. This means may comprise simply manually controlled valves, such as the valves Ila and I9b, in the branches I3 and I9 respectively. Preferably, however, the selective delivery is controlled automatically. To this end branch conduit I 9' has in parallel therewith a conduit I!" having therein an automatic valve Isc. This valve may vary as to specic details, but in general is of a character to be responsive to pressure in the gas space of container 20. In operation it is arranged to open and remain open when the pressure in container 20 exceeds a predetermined value.

Under certain conditions of operation and gas consumption it may be sumcient in the recharging of container 20 merely to avoid or reduce the development of excessive pressures in container I2. In such case the entire charge may be delivered through the branch I9 into the gas phase of container 20. Assuming the liquidto be a highly volatile one, such as liquid oxygen, under the pump delivery pressure the liquid will be in a subcooled state below its boiling point temperature corresponding to such pressure and will have a refrigeration capacity which will result in lowering the temperature of the gas in container 20 and the condensation of some of the gas. Normally this will occur to the extent of lowering the pressure, despite the decreased volume of the gas space as the charging proceeds. 'I'he result will be affected, of course, by whether or not the valves 24' and 26 are closed during this operation.

0f particular advantage is the method of charging through selective delivery, by which the pressure in container 2II is maintained substantially constant, that is to say, within at least a predetermined range dependent upon the degree of constancy desired and correspondingly the care and attention given to the regulation.

The arrangement shown in Fig. '1 enables this control of the pressure during recharging tobe effected manually or automaticallyr as desired. If performed manually the shut-ofi' valve I9d in conduit I9" preferably is closed andthe liquid delivered selectively to the liquidA or gas phase by manipulation of control valves 19a and lSb respectively. Delivery to the liquid phase will cause the pressure to rise, whereas delivery to the gas phase will ordinarily cause the pressure to decrease. A suitable pressure gauge, such as shown at 33, is provided to indicate the pressure and the required adjustment of the controls as the charging of container 20 proceeds. If desired the conduit I9 may be provided with a slight resistance, such as a spring pressed check valve shown diagrammatically at |9e, in which case valve I 9a may be left open and the amount of delivery through conduit I9 determined by adjustment of valve lsb, the delivery being substantially all through conduit I9' Awhen valve i917 is wide open.

For automatic control, valve |9b is completely closed and valves ma and 59d completely open. Automatic valve Mic isv set to open when the pressure in container 20 exceeds a predetermined value, as, for example, 150 lbs. per sq. inch gauge. if the pressure is below that value the delivery will be through the liquid phase line i! until a pressure is reached above the predetermined value when valve we will open and delivery will then continue through the gas phase line i9" until the pressure drops suillciently to cause valve idc to close.

Either or both of the valves 2d' and 26' may be open or closed during recharging, depending upon the character of the installation and circumstances in general. If, for example, either or both are open, any withdrawal during the recharging will contribute proportionately toward keeping the pressure down in container 20.

Both valves may be closed if it is desired toA isolate the container from the withdrawal system, in which case pressure control is effected entirely through the selective illling.

For most installations the main container i2 would be under low or atmospheric pressure and correspondingly of light weight economical construction, and there would be no need for, nor particular advantage in, a pressure equalization line between the two containers. A connection of that character may be provided, however, and such a one is shown in the drawing at 35 which includes a flexible coupling part 35 and appropriate shut-off valves 36 and 3l. This line may conveniently connect, as shown, into a branch 3 i of the pump priming line 3 i. f

Since certain changes in carrying out the A above method and in the constructions set forth,

which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be insuch as to maintain the pressure in the container within predetermined limits.

2. A method of charging under pressure a container for highly volatile liquefied gas, the liquid at the delivery pressure being at a temperature substantially below its boiling point corresponding to such pressure, comprising selectively apportioning the delivery of the liquid between the liquid and gas phases of the container contents in amounts such as to restrict the increase in pressure resulting from the progressively reduced gas space not to exceed a predetermined value.

3. A method of charging under pressure a container with a highly volatile liqueiled gas, comprising selectively delivering the liquid to the liquid and gas phases of the container contents, the amount delivered into the gas phase being controlled and made sullcient so that the refrigeration o! the gaseous contents serves to prevent the development of pressure within the container during the charging operation above a predetermined limit.

4. A method of charging a closed container under pressure with a liqueed gas having a boiling point temperature below 273 K. at atmospheric pressure, comprising selectively apportioning the delivery between the liquid and gas phases of the container contents such 'that the amount delivered into the gas phase is sulficient by the refrigeration eect thereon to compensate for the reduced volume of gas space and to prevent a rise in pressure above a predetermined limit.

5. A method of charging a container under pressure with a highly volatile liquefied gas, the

' liquid at the delivery pressure being in a subcooled state substantially below its boiling point corresponding to such pressure, said method comprising delivering the liquid in part tothe liquid phase contents of the container and in part to the gas phase contents, the latter causing a cooling and partial condensation of the gas, the respective amounts being apportioned such as to restrict the pressure rise in the container to not greater than a predetermined limit.

6. A method of charging under pressure a container with .a highly volatile liquefied gas, the delivered liquid being at a temperature below its boiling point corresponding to the delivery pressure, comprising delivering the' liquid in part to the liquid phase and in part into the gas phase, and apportioning the respective amounts such that-the refrigeration effect on the gas compeusates for the decrease in the volume of the gas space and the pressure within the container is maintained substantially constant.

7. In a system for storing and dispensing liquefied gas material, a first container, a second container, and means for delivering liquid from said rst container to said second container under elevated pressure embodying conduits and controls therefor for selectively delivering the liquid to the liquid or gas phase contents of said second container in apportioned amounts to control the pressure in saidsecond container.

8. In a system for storing and dispensing liqueied gas material, a first container, a second container, means for delivering liquid from said first container to said second container at elevated pressure, a delivery line from said means connected directly to the normal liquid phase space of said second container, a delivery line from said means connected directly to the normal gas phase space of said second container, and automeans connected directly to the normal liquid 10 phase space of said second container, a delivery line from said pump means connected directly to the normal gas phase space of said second container, and automatic means responsive to pressure in said second container for controlling selectively the delivery through said lines and to maintain the pressure in said second container below a predetermined value.

ODD A. HANSEN. l 

